Flourescent lights or tubes are now available in a variety of lengths and diameters. The advent of improved electronics, interior phosphor coatings and internal gases have resulted in more efficient lighting systems. As a consequence, one can now achieve the same, or higher, lighting output from a much smaller fluorescent tube.
The diameter of a fluorescent tube is normally expressed as a xe2x80x9cTxe2x80x9d number, where each T unit represents one-eighth of an inch. Traditional fluorescent tubes bore a xe2x80x9cT12xe2x80x9d designation (i.e., 1.5 inches in diameter). These large-diameter lamps are gradually being replaced by smaller-diameter tubes, for example, the xe2x80x9cT5xe2x80x9d lamp which is ⅝ inches in diameter.
The special advantages of the new T5-Technology make it worthwhile to change the numerous lights, which were installed many years ago and which are, because of their cheap choke power supply units, not very efficient. The new T5-lamps, which function solely with electronic power supply units, will mean up to 40% reduction in the consumption of electricity.
However the new T5-lamps cannot be used as they are in existing apparatus. First there is a requirement for an electronic high-frequency power supply unit; however, about 80% of the currently installed lights still function with cheap, out-dated inductive power supply chokes. Secondly the T5-lamps are about 4 to 5 cm shorter and also have pins with a considerably smaller gap between them. For this reason the T5 lamps cannot be used in existing old light fixtures.
There are already adapter systems available which allow the change over from the old to new lamps but they are expensive and complicated.
The task of the invention is to offer a solution which can be understood and used even by every non-expert.
Anyone can install or change the old luminous lamps T12, T10 or T8. Therefore the solution of the invention lies therein that one creates a so-called semi-fitting, which looks practically the same and can also be handled in the same way as the previous lamps. The semi-fitting is used as a commonly familiar luminous lamp and secured by turning.
This is carried out in that one covers the new T5 lamp with an external tube, of about the same dimensions as the previous xe2x80x9coldxe2x80x9d lamp and, since they are shorter, one can either place insulation caps at the ends, which not only compensate for the difference in length, but are also provided with contact pins, which correspond to the old standards.
Since even T5 lamps have an end it is useful, to make at least one of the insulation caps removable with a tool, in order to change the lamps. The use can be simplified in that one provides funnel-shaped receptacles at the insulation caps, in order have easy access to the pair of plug contacts of the semi-light fitting.
The attachment of the funnel-shaped receptacles on the printed circuit boards is also useful especially if the funnels can be attached on the printed circuit boards at different intervals, in order to adjust them to the varying lengths of T-5 and the previous T-8 or T-10 lamps.
Likewise, one should be able to fix the arrangement of the cushioned plug pins on the printed circuit board at various intervals for the same reason.
The arrangement of electronic components which provide the option of operating the T-5 lamps with direct current, is recommended as per the invention for reducing the effect of ensuing interfering voltage.
The positioning of a reflector in such a way that it can serve its purpose reliably when changing the lamp is of great importance as per this invention. It is recommended that the reflector be attached directly on the T5-lamp, in order to be able to push in the same with the T-5 lamp together in the external tube.
The following illustrations should show the advantage of the invention, without restricting in any way the direct protection area shown in the pictures or descriptions.